Such a heavy-duty circuit breaker and such a method are known, for example, from the document DE 100 03 359 C1. This describes a heavy-duty circuit breaker having two moveable arcing contact pieces and a heating chamber for temporarily storing quenching gas, which has been heated by an arc which may burn between the arcing contact pieces. The breaker has an insulating nozzle, which has a throat for guiding a quenching gas flow, which throat in turn is connected to the heating chamber by means of a channel. At first, the two contact pieces move in opposite directions, wherein the contact separation takes place and the throat is at least partially blocked by the second of the two contact pieces. While the throat is still at least partially closed by the second contact piece, a reversal of the movement direction of the second contact piece takes place. The second contact piece therefore moves in the same direction as the first of the two contact pieces. As a result of the fact that the throat is still at least partially blocked by the second contact piece during the movement direction reversal, an increase in the quenching gas pressure in the heating chamber can be produced. Thus, more powerful arc blowing can be achieved.